Would a graphics card help with this old pc

 From:  Matadem
11476.1 
Good day.
I was given an old pc
I7- 4790 3.6Ghz 20 gb of ram.
Moi is laggy even with simple stuff.

What would be a good video card be to upgrade this pc ..how many gb? or anything else I should look at.
I use this just for simple cad stuff.

On my Dell xps laptop it runs smooth.

Thank you!